1. Field of Invention
The invention relates to a method for the heating of solutions, preferably dialysis solutions, as described herein.
The dialysis solutions preferably treated in accordance with the invention are used, for example, in the field of peritoneal dialysis. In peritoneal dialysis, the dialysis solution to be infused into the abdominal cavity should be approximately at body temperature. On the one hand, this is perceived as pleasant by the patient and, on the other hand, is beneficial to the health. Another application is in the area of infusion technology, blood transfusion technology or other similar areas in which the liquids have to be heated.
The invention equally relates to an apparatus, in particular in a peritoneal dialysis device, for the heating of solutions, preferably dialysis solutions, as described herein.
2. Description of the Prior Art
It is already known to achieve the temperature of dialysis solutions to be used in peritoneal dialysis before the infusion. EP 0 956 876 B1, for example, describes a cassette for the conveying of dialysis liquids in which the dialysis liquid is heated before the infusion. For this purpose, the lines conducting the dialysis liquid are arranged in spiral manner in a heatable region of the cassette.
In accordance with WO 88/09186 A1 and WO 97/09074 A2, the dialysis solution to be heated is presented in a bag and is heated in this form. In this connection, a heater serves the heating of the bag in WO 97/09074 A2.
The heating time should be minimized as much as possible during the heating of the dialysis solution. However, the starting temperature of the heater for the heating of the dialysis solution having ambient temperature cannot be selected to be at any desired level. In the case a heater is used, on the one hand, the heat stability of the dialysis solution itself and, on the other hand, the heat stability of the bag material must be taken into consideration. Furthermore, particularly for the case that the heater system is accessible to the operator, it must be configured such that a risk of injury due to burns at a correspondingly hot heater can reliably be precluded.
There is a further problem in the so-called overshooting of the heating temperature which results as follows. To achieve the fastest possible heating of the bag contents, the heating device could preferably be operated at a maximum limit temperature which takes account of the previously mentioned conditions. If, however, the bag is removed from the heater during the heating of the heater or after a corresponding reaching of the wanted desired temperature of the bag, accumulated heat arises on the heater and thereby a heat accumulation which allows the temperature to rise briefly above the permitted limit temperature. This exceeding of the limit temperature can be called overshooting. On this uncontrolled exceeding of the limit temperature, there is an acute risk of burning for the user.